Formation of boride barrier layers using chemisorption techniques

ABSTRACT

A method of forming a boride layer for integrated circuit fabrication is disclosed. In one embodiment, the boride layer is formed by chemisorbing monolayers of a boron-containing compound and one refractory metal compound onto a substrate. In an alternate embodiment, the boride layer has a composite structure. The composite boride layer structure comprises two or more refractory metals. The composite boride layer is formed by sequentially chemisorbing monolayers of a boron compound and two or more refractory metal compounds on a substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of co-pending U.S. patentapplication Ser. No. 09/604,943, filed Jun. 27, 2000, which is hereinincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to the formation of boride barrierlayers and, more particularly to boride barrier layers formed usingchemisorption techniques.

[0004] 2. Description of the Related Art

[0005] In the manufacture of integrated circuits, barrier layers areoften used to inhibit the diffusion of metals and other impurities intoregions underlying such barrier layers. These underlying regions mayinclude transistor gates, capacitor dielectric, semiconductorsubstrates, metal lines, as well as many other structures that appear inintegrated circuits.

[0006] For the current subhalf-micron (0.5 μm) generation ofsemiconductor devices, any microscopic reaction at an interface betweeninterconnection layers can cause degradation of the resulting integratedcircuits (e. g., increase the resistivity of the interconnectionlayers). Consequently, barrier layers have become a critical componentfor improving the reliability of interconnect metallization schemes.

[0007] Compounds of refractory metals such as, for example, nitrides,borides, and carbides have been suggested as diffusion barriers becauseof their chemical inertness and low resistivities (e. g., resistivitiestypically less than about 200 μΩ-cm). In particular, borides such as,for example, titanium diboride (TiB₂) have been suggested for use as abarrier material since layers formed thereof generally have lowresistivities (e. g., resistivities less than about 150 μΩ-cm).

[0008] Boride barrier layers are typically formed using chemical vapordeposition (CVD) techniques. For example, titanium tetrachloride (TiCl₄)may be reacted with diborane (B₂H₆) to form titanium diboride (TiB₂)using CVD. However, when Cl-based chemistries are used to form boridebarrier layers, reliability problems can occur. In particular, boridelayers formed using CVD chlorine-based chemistries typically have a highchlorine (Cl) content (e. g., chlorine content greater than about 3%). Ahigh chlorine content is undesirable because the chlorine may migratefrom the boride barrier layer into adjacent interconnection layers,which can increase the contact resistance of such interconnection layersand potentially change the characteristics of integrated circuits madetherefrom.

[0009] Therefore, a need exists in the art for reliable boride barrierlayers for integrated circuit fabrication. Particularly desirable wouldbe reliable boride barrier layers useful for interconnect structures.

SUMMARY OF THE INVENTION

[0010] Boride barrier layers for integrated circuit fabrication areprovided. In one embodiment, the boride barrier layer comprises onerefractory metal. The boride barrier layer may be formed by sequentiallychemisorbing alternating monolayers of a boron compound and a refractorymetal compound onto a substrate.

[0011] In an alternate embodiment, a composite boride barrier layer isformed. The composite boride barrier layer comprises two or morerefractory metals. The composite boride barrier layer may be formed bysequentially chemisorbing monolayers of a boron compound and two or morerefractory metal compounds onto a substrate.

[0012] The boride barrier layer is compatible with integrated circuitfabrication processes. In one integrated circuit fabrication process,the boride barrier layer comprises one refractory metal. The boridebarrier layer is formed by sequentially chemisorbing alternatingmonolayers of a boron compound and one refractory metal compound on asubstrate. Thereafter, one or more metal layers are deposited on theboride barrier layer to form an interconnect structure.

[0013] In another integrated circuit fabrication process, the boridebarrier layer has a composite structure. The composite boride barrierlayer comprises two or more refractory metals. The composite boridebarrier layer is formed by sequentially chemisorbing monolayers of aboron compound and two or more refractory metal compounds on asubstrate. Thereafter, one or more metal layers are deposited on thecomposite boride barrier layer to form an interconnect structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The teachings of the present invention can be readily understoodby considering the following detailed description in conjunction iwththe accompanying drawings, in which:

[0015]FIG. 1 depicts a schematic illustration of an apparatus that canbe used for the practice of embodiments described herein;

[0016]FIGS. 2a-2 c depict cross-sectional views of a substrate structureat different stages of integrated circuit fabrication incorporating aboride barrier layer;

[0017]FIGS. 3a-3 c depict cross-sectional views of a substrateundergoing a first sequential chemisorption

[0018] process of a boron compound and one refractory metal compound toform a boride barrier layer;

[0019]FIGS. 4a-4 d depict cross-sectional views of a substrateundergoing a second sequential chemisorption process of a boron compoundand two refractory metal compounds to form a composite boride barrierlayer;

[0020]FIGS. 5a-5 d depict cross-sectional views of a substrateundergoing a third sequential chemisorption of a boron compound and tworefractory metal compounds to form a composite boride barrier layer; and

[0021]FIGS. 6a-6 c depict cross-sectional views of a substrate structureat different stages of integrated circuit fabrication incorporating morethan one boride barrier layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022]FIG. 1 depicts a schematic illustration of a wafer processingsystem 10 that can be used to form boride barrier layers in accordancewith embodiments described herein. The system 10 comprises a processchamber 100, a gas panel 130, a control unit 110, along with otherhardware components such as power supplies 106 and vacuum pumps 102. Thesalient features of process chamber 100 are briefly described below.

[0023] Chamber 100

[0024] The process chamber 100 generally houses a support pedestal 150,which is used to support a substrate such as a semiconductor wafer 190within the process chamber 100. Depending on the specific process, thesemiconductor wafer 190 can be heated to some desired temperature priorto layer formation.

[0025] In chamber 100, the wafer support pedestal 150 is heated by anembedded heater 170. For example, the pedestal 150 may be resistivelyheated by applying an electric current from an AC power supply 106 tothe heater element 170. The wafer 190 is, in turn, heated by thepedestal 150, and can be maintained within a desired process temperaturerange of, for example, about 20° C. to about 500° C.

[0026] A temperature sensor 172, such as a thermocouple, is alsoembedded in the wafer support pedestal 150 to monitor the temperature ofthe pedestal 150 in a conventional manner. For example, the measuredtemperature may be used in a feedback loop to control the electriccurrent applied to the heater element 170 by the power supply 106, suchthat the wafer temperature can be maintained or controlled at a desiredtemperature that is suitable for the particular process application. Thepedestal 150 is optionally, heated using radiant heat (not shown).

[0027] A vacuum pump 102 is used to evacuate process gases from theprocess chamber 100 and to help maintain the desired pressure inside thechamber 100. An orifice 120 is used to introduce process gases into theprocess chamber 100. The dimensions of the orifice 120 are variable andtypically depend on the size of the process chamber 100.

[0028] The orifice 120 is coupled to a gas panel 130 via a valve 125.The gas panel 130 provides process gases from two or more gas sources135, 136 to the process chamber 100 through orifice 120 and valve 125.The gas panel 130 also provides a purge gas from a purge gas source 138to the process chamber 100 through orifice 120 and valve 125.

[0029] A control unit 110, such as a computer, controls the flow ofvarious process gases through the gas panel 130 as well as valve 125during the different steps of a wafer process sequence. Illustratively,the control unit 110 comprises a central processing unit (CPU) 112,support circuitry 114, and memories containing associated controlsoftware 116. In addition to the control of process gases through thegas panel 130, the control unit 110 is also responsible for automatedcontrol of the numerous steps required for wafer processing—such aswafer transport, temperature control, chamber evacuation, among othersteps.

[0030] The control unit 110 may be one of any form of general purposecomputer processor that can be used in an industrial setting forcontrolling various chambers and sub-processors. The computer processormay use any suitable memory, such as random access memory, read onlymemory, floppy disk drive, hard disk, or any other form of digitalstorage, local or remote. Various support circuits may be coupled to thecomputer processor for supporting the processor in a conventionalmanner. Software routines as required may be stored in the memory orexecuted by a second processor that is remotely located. Bi-directionalcommunications between the control unit 110 and the various componentsof the wafer processing system 10 are handled through numerous signalcables collectively referred to as signal buses 118, some of which areillustrated in FIG. 1.

[0031] Boride Barrier Layer Formation

[0032]FIGS. 2a-2 c illustrate one preferred embodiment of boride layerformation for integrated circuit fabrication of an interconnectstructure. In general, the substrate 200 refers to any workpiece uponwhich film processing is performed, and a substrate structure 250 isused to generally denote the substrate 200 as well as other materiallayers formed on the substrate 200. Depending on the specific stage ofprocessing, the substrate 200 may be a silicon semiconductor wafer, orother material layer, which has been formed on the wafer. FIG. 2a, forexample, shows a cross-sectional view of a substrate structure 250,having a material layer 202 thereon. In this particular illustration,the material layer 202 may be an oxide (e. g., silicon dioxide). Thematerial layer 202 has been conventionally formed and patterned toprovide a contact hole 202H extending to the top surface 200T of thesubstrate 200.

[0033]FIG. 2b shows a boride layer 204 conformably formed on thesubstrate structure 250. The boride layer 204 is formed by chemisorbingmonolayers of a boron-containing compound and a refractory metalcompound on the substrate structure 250.

[0034] The monolayers are chemisorbed by sequentially providing aboron-containing compound and one or more refractory metal compounds toa process chamber. In a first sequential chemisorption process, themonolayers of the boron-containing compound and one refractory metalcompound are alternately chemisorbed on a substrate 300 as shown inFIGS. 3a-3 c.

[0035]FIG. 3a depicts a cross-sectional view of a substrate 300, whichmay be in a stage of integrated circuit fabrication. A monolayer of aboron-containing compound 305 is chemisorbed on the substrate 300 byintroducing a pulse of a boron-containing gas into a process chambersimilar to that shown in FIG. 1. The boron-containing compound typicallycombines boron atoms 310 with one or more reactive species b 315. Duringboride layer formation, the reactive species b 315 form byproducts thatare transported from the substrate 300 surface by the vacuum system.

[0036] The chemisorbed monolayer of the boron-containing compound 305 isself-limiting in that only one monolayer may be chemisorbed onto thesubstrate 300 surface during a given pulse. Only one monolayer of theboron-containing compound is chemisorbed on the substrate because thesubstrate has a limited surface area. This limited surface area providesa finite number of sites for chemisorbing the boron-containing compound.Once the finite number of sites are occupied by the boron-containingcompound, further chemisorption of the boron-containing compound will beblocked.

[0037] The boron-containing compound may be for example a boranecompound having the general formula B_(x)H_(y), where x has a rangebetween 1 and 10, and y has a range between 3 and 30. For example,borane (BH₃), diborane (B₂H₆), triborane (B₃H₉), tetraborane (B₄H₁₂),pentaborane (B₅H₁₅), hexaborane (B₆H₁₈), heptaborane (B₇H₂₁), octaborane(B₈H₂₄), nanoborane (B₉H₂₇), and decaborane (B₁₀H₃₀), may be used as theboron-containing compound.

[0038] After the monolayer of the boron compound is chemisorbed onto thesubstrate 300, excess boron-containing compound is removed from theprocess chamber by introducing a pulse of a purge gas thereto. Purgegases such as, for example helium (He), argon (Ar), nitrogen (N₂),ammonia (NH₃), and hydrogen (H₂), among others may be used.

[0039] After the process chamber has been purged, a pulse of onerefractory metal compound is introduced into the process chamber.Referring to FIG. 3b, a layer of the refractory metal compound 307 ischemisorbed on the boron monolayer 305. The refractory metal compoundtypically combines refractory metal atoms 320 with one or more reactivespecies a 325.

[0040] The chemisorbed monolayer of the refractory metal compound 307reacts with the boron-containing monolayer 305 to form a boride layer309. The reactive species a 325 and b 315 form byproducts ab 330 thatare transported from the substrate 300 surface by the vacuum system. Thereaction of the refractory metal compound 307 with the boron monolayer305 is self-limited, since only one monolayer of the boron compound waschemisorbed onto the substrate 300 surface.

[0041] The refractory metal compound may include refractory metals suchas for example titanium (Ti), tungsten (W), tantalum (Ta), zirconium(Zr), hafnium (Hf), molybdenum (Mo), niobium (Nb), vanadium (V), andchromium (Cr), among others combined with reactive species such as, forexample chlorine (Cl) and fluorine (F). For example, titaniumtetrachloride (TiCl₄), tungsten hexafluoride (WF₆), tantalumpentachloride (TaCl₅), zirconium tetrachloride (ZrCl₄), hafniumtetrachloride (HfCl₄), molybdenum pentachloride (MoCl₅), niobiumpentachloride (NbCl₅), vanadium pentachloride (VCl₅), chromiumtetrachloride (CrCl₄) may be used as the refractory metal compound.

[0042] After the monolayer of the refractory metal compound ischemisorbed onto the substrate 300, any excess refractory metal compoundis removed from the process chamber by introducing another pulse of thepurge gas therein. Thereafter, as shown in FIG. 3c, the boride layerdeposition sequence of alternating monolayers of the boron-containingcompound and the refractory metal compound are repeated until a desiredboride layer thickness is achieved. The boride layer may, for example,have a thickness in a range of about 200 Å to about 5000 Å, and morepreferably, about 2500 Å.

[0043] In FIGS. 3a-3 c, boride layer formation is depicted as startingwith the chemisorption of a boron-containing monolayer on the substratefollowed by a monolayer of a refractory metal compound. Alternatively,the boride layer formation may start with the chemisorption of amonolayer of a refractory metal compound on the substrate followed by amonolayer of the boron-containing compound.

[0044] The pulse time for each pulse of the boron-containing compound,the one or more refractory metal compounds, and the purge gas isvariable and depends on the volume capacity of the deposition chamber aswell as the vacuum system coupled thereto. Similarly, the time betweeneach pulse is also variable and depends on the volume capacity of theprocess chamber as well as the vacuum system coupled thereto.

[0045] In general, the alternating monolayers may be chemisorbed at asubstrate temperature less than about 500° C., and a chamber pressureless than about 100 torr. A pulse time of less than about 1 second forthe boron-containing compound, and a pulse time of less than about 1second for the refractory metal compounds are typically sufficient tochemisorb the alternating monolayers that comprise the boride layer onthe substrate. A pulse time of less than about 1 second for the purgegas is typically sufficient to remove the reaction byproducts as well asany residual materials remaining in the process chamber.

[0046] In a second chemisorption process, the boron-containingmonolayers and two or more refractory metal compounds are alternatelychemisorbed on the substrate to form a composite boride layer. FIG. 4adepicts a cross-sectional view of a substrate 400, which may be in astage of integrated circuit fabrication. A self-limiting monolayer of aboron-containing compound 405 is chemisorbed on the substrate 400 byintroducing a pulse of a boron-containing compound into a processchamber similar to that shown in FIG. 1 according to the processconditions described above with reference to FIGS. 2a-2 c. Theboron-containing compound combines boron atoms 410 with one or morereactive species b 415.

[0047] After the monolayer of the boron compound 405 is chemisorbed ontothe substrate 400, excess boron-containing compound is removed from theprocess chamber by introducing a pulse of a purge gas thereto.

[0048] Referring to FIG. 4b, after the process chamber has been purged,a pulse of a first refractory metal compound M₁a₁ is introduced into theprocess chamber. A layer of the first refractory metal compound 407 ischemisorbed on the boron monolayer 405. The first refractory metalcompound typically combines first refractory metal atoms M₁ 420 with oneor more reactive species a₁ 425.

[0049] The chemisorbed monolayer of the first refractory metal compound407 reacts with the boron-containing monolayer 405 to form a boridemonolayer 409. The reactive species a₁ 425 and b 415 form byproducts a₁b430 that are transported from the substrate 400 surface by the vacuumsystem.

[0050] After the monolayer of the first refractory metal compound 407 ischemisorbed onto the substrate 400, the excess first refractory metalcompound M₁a₁ is removed from the process chamber by introducing anotherpulse of the purge gas therein.

[0051] Another pulse of the boron-containing compound is than introducedinto the process chamber. A monolayer of the boron-containing compound405 is chemisorbed on the first refractory metal monolayer 407, as shownin FIG. 4c. The chemisorbed monolayer of the boron-containing compound405 reacts with the first refractory metal monolayer 407 to form aboride layer 409. The reactive species a₁ 425 and b 415 form byproductsa₁b 430 that are transported from the substrate 400 surface by thevacuum system.

[0052] After the monolayer of the boron compound 405 is chemisorbed ontothe first refractive metal monolayer 407, excess boron-containingcompound is removed from the process chamber by introducing a pulse of apurge gas thereto.

[0053] Referring to FIG. 4d, after the process chamber has been purged,a pulse of a second refractory metal compound M₂a₁ is introduced intothe process chamber. A layer of the second refractory metal compound 411is chemisorbed on the boron monolayer 405. The second refractory metalcompound typically combines second refractory metal atoms M₂ 440 withone or more reactive species a₁ 425.

[0054] The chemisorbed monolayer of the second refractory metal compound411 reacts with the boron-containing monolayer 405 to form the compositeboride layer 409. The reactive species a₁ 425 and b 415 form byproductsa₁b 430 that are transported from the substrate 400 surface by thevacuum system.

[0055] After the monolayer of the second refractory metal compound 411is chemisorbed onto the substrate 400, the excess second refractorymetal compound M₂a₁ is removed from the process chamber by introducinganother pulse of the purge gas therein.

[0056] Thereafter, the boride layer deposition sequence of alternatingmonolayers of the boron-containing compound and the two refractory metalcompounds M₁a₁ and M₂a₁ are repeated until a desired boride layerthickness is achieved.

[0057] In FIGS. 4a-4 d, boride layer formation is depicted as startingwith the chemisorption of the boron-containing monolayer on thesubstrate followed by monolayers of the two refractory metal compounds.Alternatively, the boride layer formation may start with thechemisorption of monolayers of either of the two refractory metalcompounds on the substrate followed by monolayers of theboron-containing compound. Optionally, monolayers of more than tworefractory metal compounds may be chemisorbed on the substrate 400.

[0058] In a third chemisorption process, the boron-containing monolayersand two or more refractory metal compounds are alternately chemisorbedon the substrate to form a composite boride layer, as illustrated inFIGS. 5a-5 d.

[0059]FIG. 5a depicts a cross-sectional view of a substrate 500, whichmay be in a stage of integrated circuit fabrication. A self-limitingmonolayer of a first refractory metal compound 507 is chemisorbed on thesubstrate 500 by introducing a pulse of a first refractory metalcompound M₁a₁ into a process chamber similar to that shown in FIG. 1according to the process conditions described above with reference toFIGS. 2a-2 c.

[0060] After the monolayer of the first refractory metal compound 507 ischemisorbed onto the substrate 500, excess first refractory metalcompound is removed from the process chamber by introducing a pulse of apurge gas thereto.

[0061] Referring to FIG. 5b, after the process chamber has been purged,a pulse of a second refractory metal compound M₂a₁ is introduced intothe process chamber. A layer of the second refractory metal compound 511is chemisorbed on the first refractory metal monolayer 507.

[0062] After the monolayer of the second refractory metal compound 511is chemisorbed onto the substrate 500, the excess second refractorymetal compound M₂a₁ is removed from the process chamber by introducinganother pulse of the purge gas therein.

[0063] A pulse of a boron-containing compound is than introduced intothe process chamber. A monolayer of the boron-containing compound 505 ischemisorbed on the second refractory metal monolayer 511, as shown inFIG. 5c. The chemisorbed monolayer of the boron-containing compound 505reacts with the second refractory metal monolayer 511 to form acomposite boride layer 509. The reactive species a₁ 525 and b 515 formbyproducts a₁b 530 that are transported from the substrate 500 surfaceby the vacuum system.

[0064] After the monolayer of the boron compound 505 is chemisorbed ontothe second refractory metal monolayer 511, excess boron-containingcompound is removed from the process chamber by introducing a pulse of apurge gas thereto.

[0065] Referring to FIG. 5d, after the process chamber has been purged,a pulse of the first refractory metal compound M₁a₁ is introduced intothe process chamber. A monolayer of the first refractory metal compound507 is chemisorbed on the boron monolayer 505.

[0066] The chemisorbed monolayer of the first refractory metal compound507 reacts with the boron-containing monolayer 505 to form the boridemonolayer 509. The reactive species a₁ 525 and b 515 form byproducts a₁b530 that are transported from the substrate 500 surface by the vacuumsystem.

[0067] After the monolayer of the first refractory metal compound 507 ischemisorbed onto the substrate 500, the excess first refractory metalcompound M₁a₁ is removed from the process chamber by introducing anotherpulse of the purge gas therein.

[0068] Thereafter, the boride layer deposition sequence of alternatingmonolayers of the boron-containing compound and the two refractory metalcompounds M₁a₁ and M₂a₁ are repeated until a desired boride layerthickness is achieved.

[0069] In FIGS. 5a-5 d, boride layer formation is depicted as startingwith the chemisorption of the first refractory metal monolayer on thesubstrate followed by monolayers of the second refractory metal compoundand the boron-containing compound. Alternatively, the boride layerformation may start with the chemisorption of the monolayer of theboron-containing compound on the substrate followed by the monolayers ofthe two refractory metal compounds. Optionally, monolayers of more thantwo refractory metal compounds may be chemisorbed on the substrate 500.

[0070] The sequential deposition processes described aboveadvantageously provide good step coverage for the boride layer, due tothe monolayer chemisorption mechanism used for forming the boride layer.In particular, boride layer formation using the monolayer chemisorptionmechanism is believed to contribute to a near perfect step coverage overcomplex substrate topographies.

[0071] Furthermore, in chemisorption processes, since only one monolayermay be absorbed on the topographic surface, the size of the depositionarea is largely independent of the amount of precursor gas remaining inthe reaction chamber once a monolayer has been formed.

[0072] Referring to FIG. 2c, after the formation of the boride layer204, a contact layer 206 may be formed thereon to complete theinterconnect structure. The contact layer 206 is preferably selectedfrom the group of aluminum (Al), copper (Cu), tungsten (W), andcombinations thereof.

[0073] The contact layer 206 may be formed, for example, using chemicalvapor deposition (CVD), physical vapor deposition (PVD), or acombination of both CVD and PVD. For example, an aluminum (Al) layer maybe deposited from a reaction of a gas mixture containing dimethylaluminum hydride (DMAH) and hydrogen (H₂) or argon (Ar) or other DMAHcontaining compounds, a CVD copper layer may be deposited from a gasmixture containing Cu⁺²(hfac)₂ (copper hexafluoro acetylacetonate),Cu⁺²(fod)₂ (copper heptafluoro dimethyl octanediene), Cu⁺¹hfac TMVS(copper hexafluoro acetylacetonate trimethylvinylsilane), orcombinations thereof, and a CVD tungsten layer may be deposited from agas mixture containing tungsten hexafluoride (WF₆). A PVD layer isdeposited from a copper target, an aluminum target, or a tungstentarget.

[0074]FIGS. 6a-6 c illustrate an alternate embodiment of boride layerformation for integrated circuit fabrication of the interconnectstructure. In general, the substrate 600 refers to any workpiece uponwhich film processing is performed, and a substrate structure 650 isused to generally denote the substrate 600 as well as other materiallayers formed on the substrate 600. Depending on the specific stage ofprocessing, the substrate 600 may be a silicon semiconductor wafer, orother material layer, which has been formed on the wafer. FIG. 6a, forexample, shows a cross-sectional view of a substrate structure 650,having a material layer 602 thereon. In this particular illustration,the material layer 602 may be an oxide (e. g., silicon dioxide). Thematerial layer 602 has been conventionally formed and patterned toprovide a contact hole 602H extending to the top surface 600T of thesubstrate 600.

[0075]FIG. 6b shows two boride layers 604, 606 conformably formed on thesubstrate structure 650. The boride layers 604, 606 are formed bychemisorbing monolayers of a boron-containing compound and one or morerefractory metal compounds on the substrate structure 650 as describedabove with reference to FIGS. 3a-5 d. The two boride layers 604, 606 mayeach comprise one or more refractory metals. The thicknesses of the twoor more boride layers 604, 606 may be variable depending on the specificstage of processing. Each boride layer 604, 606 may, for example, have athickness in a range of about 200 Å to about 5000 Å.

[0076] Referring to FIG. 6c, after the formation of the boride layers604, 606, a contact layer 608 may be formed thereon to complete theinterconnect structure. The contact layer 608 is preferably selectedfrom the group of aluminum (Al), copper (Cu), tungsten (W), andcombinations thereof.

[0077] The specific process conditions disclosed in the above discussionare meant for illustrative purposes only. Other combinations of processparameters such as precursor and inert gases, flow ranges, pressure andtemperature may also be used in forming the boride layer of the presentinvention.

[0078] Although several preferred embodiments, which incorporate theteachings of the present invention, have been shown and described indetail, those skilled in the art can readily devise many other variedembodiments that still incorporate these teachings.

1. A method of forming a film on a substrate, comprising: positioningthe substrate having an oxide layer thereon; and forming at least onemetal boride layer on at least a portion of the substrate bysequentially chemisorbing monolayers of a boron-containing compound andone or more refractory metal compounds on the substrate to form the atleast one metal boride layer thereon, wherein the at least one metalboride layer is formed using a sequential chemisorption process.
 2. Themethod of claim 1, wherein the substrate is subjected to a purge gasfollowing chemisorption of each monolayer.
 3. The method of claim 1,wherein the boron-containing compound has a general formula B_(x)H_(y),where x has a range between 1 and 10, and y has a range between 3 and30.
 4. The method of claim 3, wherein the boron-containing compound isselected from the group consisting of borane, diborane, triborane,tetraborane, pentaborane, hexaborane, heptaborane, octaborane,nanoborane and decaborane.
 5. The method of claim 1, wherein the one ormore refractory metal compounds are selected from the group consistingof titanium tetrachloride, tungsten hexafluoride, tantalumpentachloride, zirconium tetrachloride, hafnium tetrachloride,molybdenum pentachloride, niobium pentachloride, vanadium chloride, andchromium chloride.
 6. The method of claim 1, wherein forming at leastone metal boride layer is performed at a temperature less than about500° C.
 7. The method of claim 1, wherein forming at least one metalboride layer is performed at a pressure less than about 100 Torr.
 8. Themethod of claim 2, wherein the purge gas is selected from the group ofhelium, argon, hydrogen, nitrogen, ammonia, and combinations thereof. 9.The method of claim 1, wherein monolayers of the boron-containingcompound and the one or more refractory metal compounds are alternatelychemisorbed on the substrate.
 10. The method of claim 9, wherein onemonolayer of the boron-containing compound is chemisorbed between eachchemisorbed monolayer of the one or more refractory metal compounds. 11.The method of claim 9, wherein one monolayer of the boron-containingcompound is chemisorbed on the substrate after two or more monolayers ofthe one or more refractory metal compounds are chemisorbed thereon. 12.The method of claim 1, wherein the at least one metal boride layer has athickness less than about 100 Å.
 13. The method of claim 1, wherein theat least one metal boride layer has a thickness in a range of from about200 Å to about 5,000 Å.
 14. A method of forming a layer on a substratefor use in integrated circuit fabrication, comprising: positioning thesubstrate having an oxide layer thereon; forming a first boride layercomprising one or more refractory metals on at least a portion of thesubstrate by chemisorbing monolayers of a boron-containing compound andone or more refractory metal compounds on the substrate; and forming asecond boride layer comprising one or more refractory metals on thefirst boride layer by chemisorbing monolayers of a boron-containingcompound and one or more refractory metal compounds on the substrate.15. A method of film deposition for integrated circuit fabrication,comprising: placing a substrate within a deposition chamber; introducinga boron-containing compound into the chamber; chemisorbing at least aportion of the boron-containing compound to the substrate at conditionssufficient to form a boron-containing layer; evacuating the chamber;introducing at least one refractory metal compound into the chamber;reacting a portion of the at least one refractory metal compound withthe boron-containing layer at conditions sufficient to form a metalboride containing layer; and evacuating the chamber.
 16. The method ofclaim 15, wherein the metal boride containing layer comprises at leastone refractory metal selected from the group consisting of titanium,tungsten, vanadium, niobium, tantalum, zirconium, hafnium, chromium andmolybdenum.
 17. The method of claim 15, wherein the at least onerefractory metal compound is selected from the group consisting oftitanium tetrachloride, tungsten hexafluoride, tantalum pentachloride,zirconium tetrachloride, hafnium tetrachloride, molybdenumpentachloride, niobium pentachloride, vanadium chloride and chromiumchloride.
 18. The method of claim 15, wherein the boron-containingcompound has the general formula B_(x)H_(y), where x has a range from 1to 10 and y has a range from 3 to
 30. 19. The method of claim 15,wherein the boron-containing compound is selected from the groupconsisting of borane, diborane, triborane, tetraborane, pentaborane,hexaborane, heptaborane, octaborane, nanoborane and decaborane.
 20. Themethod of claim 15, wherein the conditions sufficient to form the metalboride containing layer comprises a temperature of about 500° C. orless.
 21. The method of claim 15, wherein the conditions sufficient toform the metal boride containing layer comprises a pressure of about 100Torr or less.
 22. The method of claim 15, further comprising purging thedeposition chamber with at least one purge gas selected from the groupconsisting of helium, argon, hydrogen, nitrogen, ammonia andcombinations thereof.
 23. The method of claim 15, wherein the metalboride containing layer comprises at least two refractory metals. 24.The method of claim 15, wherein the metal boride containing layer has athickness from about 200 Å to about 5,000 Å.
 25. A method of filmdeposition for integrated circuit fabrication, comprising: placing asubstrate within a deposition chamber; introducing at least onerefractory metal compound into the chamber; chemisorbing a portion ofthe at least one refractory metal compound to the substrate to form arefractory metal containing layer; evacuating the chamber; introducing aboron-containing compound into the chamber; reacting at least a portionof the boron-containing compound with the refractory metal containinglayer at conditions sufficient to form a metal boride containing layer;and evacuating the chamber.
 26. The method of claim 25, wherein themetal boride containing layer comprises at least one refractory metalselected from the group consisting of titanium, tungsten, vanadium,niobium, tantalum, zirconium, hafnium, chromium and molybdenum.
 27. Themethod of claim 25, wherein the at least one refractory metal compoundis selected from the group consisting of titanium tetrachloride,tungsten hexafluoride, tantalum pentachloride, zirconium tetrachloride,hafnium tetrachloride, molybdenum pentachloride, niobium pentachloride,vanadium chloride and chromium chloride.
 28. The method of claim 25,wherein the boron-containing compound has the general formulaB_(x)H_(y), where x has a range from 1 to 10, and y has a range from 3to
 30. 29. The method of claim 25, wherein the boron-containing compoundis selected from the group consisting of borane, diborane, triborane,tetraborane, pentaborane, hexaborane, heptaborane, octaborane,nanoborane and decaborane.
 30. The method of claim 25, wherein theconditions sufficient to from the metal boride containing layercomprises a temperature of about 500° C. or less.
 31. The method ofclaim 25, wherein the conditions sufficient to form the metal boridecontaining layer comprises a pressure of about 100 Torr or less.
 32. Themethod of claim 25, further comprising purging the deposition chamberwith at least one purge gas selected from the group consisting ofhelium, argon, hydrogen, nitrogen, ammonia and combinations thereof. 33.The method of claim 25, wherein the metal boride containing layercomprises at least two refractory metals.
 34. The method of claim 25,wherein the metal boride containing layer has a thickness from about 200Å to about 5,000 Å.